Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like, conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent core. The absorbent core is typically located in between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer.
Many absorbent articles have been adapted for use in a training program, such as toilet training or enuresis control, or to provide indication of various medical, physical, or other conditions. Accordingly, various types of sensors and indicators, including moisture or wetness indicators, have been suggested for use in absorbent articles. Wetness indicators, for example, can include alarm devices that are designed to assist parents or attendants to identify a wet diaper condition upon insult. The devices produce either a visual or an audible signal.
Problems have been experienced, however, in efficiently and reliably incorporating wetness indicators into absorbent articles at the process speeds at which absorbent articles are produced. Thus, a need exists for improved wetness sensors that can be easily incorporated into absorbent articles.
Dehydration is one of the leading causes in infant mortality. Severe diarrhea can cause a 24-hour fluid loss through stools of greater than 200 milliliters per kilogram compared to a normal loss of 5 milliliters per kilogram. Severe diarrhea can also cause a 70110 millimoles/liter-water deficiency in electrolytes such as sodium and potassium. The changes of fluids and electrolytes in infants and young children can be as much as 3 times higher than that of adults due to their higher water content (approximately 70% of body weight is water in infants, 65% in children and 60% in adults).
In addition, a need also exists for sensor elements for use in a wetness indicator that are made from non-metallic materials. Incorporating metallic components into an absorbent article, for instance, can cause various problems. For instance, once the absorbent articles are packaged, the absorbent articles are typically exposed to a metal detector to ensure that no metallic contaminants have accidentally been included in the package. Making the conductive elements of a wetness indicator from a metal, however, can cause a metal detector to indicate a false positive. The incorporation of metal conductive elements into an absorbent article can also cause problems when the wearer is attempting to pass through a security gate that also includes a metal detector. Further, the presence of metal in absorbent articles inhibits or prevents reclamation of articles culled during their manufacture.